glibc/sysdeps/ieee754/dbl-64/s_issignaling.c
Joseph Myers 6f322a8947 Define HIGH_ORDER_BIT_IS_SET_FOR_SNAN to 0 or 1.
This patch moves the HIGH_ORDER_BIT_IS_SET_FOR_SNAN macro from being
defined or undefined to the preferred convention of always being
defined, to either 0 or 1, so allowing typo-proof tests with #if.

The macro is moved from math_private.h to a new header
nan-high-order-bit.h to make it easy for all architectures to define,
either through the sysdeps/generic version of the header or through
providing their own version of the header, without needing #ifndef in
the generic math_private.h to give a default definition.  The move
also allows the macro to be used without needing math_private.h to be
included; the immediate motivation of this patch is to allow tests to
access this information (to know what kinds of NaNs 0 is a valid
payload for) without needing to include math_private.h.  Existing
C level rather than preprocessor conditionals at all, but this patch
does not make such a change).

Tested for x86_64 and x86 (testsuite); also verified for x86_64, x86,
mips64 and powerpc that installed stripped shared libraries are
unchanged by the patch.

	* sysdeps/generic/nan-high-order-bit.h: New file.
	* sysdeps/hppa/nan-high-order-bit.h: Likewise.
	* sysdeps/mips/nan-high-order-bit.h: Likewise.
	* sysdeps/hppa/math_private.h: Remove file.
	* sysdeps/mips/math_private.h (HIGH_ORDER_BIT_IS_SET_FOR_SNAN): Do
	not define here.
	* sysdeps/ieee754/dbl-64/s_issignaling.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/dbl-64/s_totalorder.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/dbl-64/s_totalordermag.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_issignaling.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_totalorder.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_totalordermag.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/flt-32/s_issignalingf.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/flt-32/s_totalorderf.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/flt-32/s_totalordermagf.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-128/s_issignalingl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-128/s_totalorderl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-128/s_totalordermagl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-128ibm/s_issignalingl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-128ibm/s_totalorderl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-128ibm/s_totalordermagl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-96/s_issignalingl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-96/s_totalorderl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
	* sysdeps/ieee754/ldbl-96/s_totalordermagl.c: Include
	<nan-high-order-bit.h>.
	[HIGH_ORDER_BIT_IS_SET_FOR_SNAN]: Test with #if not #ifdef.
2016-10-17 22:48:51 +00:00

48 lines
1.8 KiB
C

/* Test for signaling NaN.
Copyright (C) 2013-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <nan-high-order-bit.h>
int
__issignaling (double x)
{
#if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
u_int32_t hxi;
GET_HIGH_WORD (hxi, x);
/* We only have to care about the high-order bit of x's significand, because
having it set (sNaN) already makes the significand different from that
used to designate infinity. */
return (hxi & 0x7ff80000) == 0x7ff80000;
#else
u_int32_t hxi, lxi;
EXTRACT_WORDS (hxi, lxi, x);
/* To keep the following comparison simple, toggle the quiet/signaling bit,
so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as
common practice for IEEE 754-1985). */
hxi ^= 0x00080000;
/* If lxi != 0, then set any suitable bit of the significand in hxi. */
hxi |= (lxi | -lxi) >> 31;
/* We have to compare for greater (instead of greater or equal), because x's
significand being all-zero designates infinity not NaN. */
return (hxi & 0x7fffffff) > 0x7ff80000;
#endif
}
libm_hidden_def (__issignaling)